Problem recieving mail

I am quite pleased with ispconfig. It is truly an amazing program. However, I am having trouble receiving e-mails in my inbox. This holds true using the webmail interface and outlook. It appears as if they are not being properly delivered to the users e-mail box. I am able to send main from the account so SMTP works perfectly. Also, no e-mails are getting bounced back.

My set up is as follows:
Fedora Core 4 perfect
MTA Postfix
logs are enabled
maildir is disabled
spamfilter is enabled

Please try to check your maillog with the command "tail -f /path/to/mail/log". This will open an continous tail command. If you now send an email to your server, which lines where added to the mail log?